This invention generally relates to hinges and, more particularly, to self-latching hinges for use in notebook computers, automobiles, furniture, or the like.
In certain hinge applications, it is desirable to provide a hinge which can maintain a hinged member in an open position or a closed position. When the hinged member is in the open position, in certain applications, such as clamshell-style phones and notebook computers, it is desirable that the hinged member be held stably in position. It is also desirable in such applications that the hinge maintain the hinged member in a closed position relative to the device housing for storage and transport. Generally in such applications, the open position is set at a fixed, predetermined angle.
One known relatively inexpensive, preassembled, self-containing, two-position hinge can hold a hinged member in a first, open position or a second, closed position relative to a device housing without imparting an axial load on the hinged member or the device housing, thereby resulting in a long operating life. The hinge uses a cam surface and a cam follower urged toward the cam surface by a spring to hold either a closed position or an open position between 130 degrees and 160 degrees relative to the device housing. Although extensively used in clamshell-style phones, this type of hinge has limited usefulness in applications which prefer a different amount of torque for closing a device than for opening a device.
In another known hinge which was designed for use in notebook computers, a higher torque is required to open the notebook computer than is required to close it. The higher torque is required in the opening direction to offset the weight of the display and allow it to be positionable at a multitude of angles with respect to the bottom housing of the notebook computer. However, this configuration requires a user to use two hands in opening the notebook computer. Also, a latch is generally required in order to ensure that the notebook computer remains closed.
It is desirable to provide a self-latching hinge which requires a higher torque in the closing direction than in the opening direction in order to allow for one-handed opening of the hinge while at the same time having minimal laxity in the open position so that a device can maintain a particular orientation when opened. It would also be desirable to have latchless closing of the device in which the hinge is installed.